TECHNICAL FIELD
[0001] The technical field generally relates to asphalt binders, asphalt paving materials,
and methods for fabricating such asphalt binders, and more particularly relates to
plastomer-modified asphalt binders that meet MSCR specifications, asphalt paving materials
with such asphalt binders, and methods for fabricating such asphalt binders.
BACKGROUND
[0002] Asphalt is commonly used as a paving material for road construction and maintenance.
Typically, asphalt, often referred to as "asphalt binder" or "asphalt cement," is
mixed with aggregate to form material used in asphalt paving. Processing and use of
this material by paving crews yield asphalt pavement. The asphalt pavement comprises
aggregate held within a continuous phase of the asphalt binder by adherence of the
asphalt binder to the aggregate.
[0003] The strength and durability of the asphalt pavement depends on various factors such
as the properties of the materials used, the interaction of the various materials,
the mix design, construction practices, and the environmental and traffic conditions
to which the pavement is exposed. To produce a mix that will have good performance
during the lifetime of the pavement, it is important to attain proper coating of the
aggregate with the asphalt with the optimum asphalt binder film thickness, good adhesion
of the asphalt onto the aggregate, and good cohesive strength of the asphalt.
[0004] Conventional pavements suffer from various types of distress modes such as permanent
deformation. Permanent deformation is a significant problem for asphalt pavement.
A road may be about 80 to about 100°C or more warmer in the summer than it is in the
winter. At warmer temperatures, asphalt pavement softens and can creep and move creating
ridges and ruts, often referred to as "rutting." Rutting of the asphalt pavement can
occur under the weight of heavy trucks or traffic that has temporarily stopped, such
as, for example, at a traffic light intersection, since rutting is dependent on both
the weight of the vehicle and the time duration of the weight application.
[0005] To reduce or prevent rutting, polymers or other materials having a relatively higher
modulus than the asphalt, or that can produce a higher modulus asphalt binder at higher
temperatures than the unmodified asphalt, are often incorporated into conventional
asphalt binders. Typical polymers used to modify asphalt binders to reduce or prevent
rutting include elastomers, such as, for example, styrene/butadiene/styrene copolymer
(SBS), and plastomers, such as, for example, polyethylene, ethylene/vinyl acetate
copolymer (EVA), and the like. Compared to elastomers, some plastomers have several
advantages such as, for example, low viscosity and better workability at both the
asphalt fabrication plant and at the paving construction site. As a result, low temperatures
can be used to process asphalt and also to pave roads. This results in significant
environmental and economic benefits. Another material used to produce higher modulus
asphalt binders is polyphosphoric acid (PPA). In many cases, however, the use of this
material is limited due to corrosivity issues, reports of premature cracking of pavements
constructed with binders modified with PPA and in some cases outright bans. Plastomers
are more easily handled than PPA and do not have the corrosivity issues
[0006] Recently, the Multiple Stress Creep Recovery (MSCR) test has been developed to evaluate
an asphalt binder's rutting resistance. Properties that can be evaluated by the MSCR
test are the non-recoverable creep compliance, J
nr, and the stress sensitivity, J
nr,diff. For certain plastomers, while they may meet J
nr standards (and traditional Performance Grade (PG) standards for that matter), their
stress sensitivity parameters J
nr,diff are higher than the allowed maximum value and, as a result, these plastomers should
be used in combination with elastomers to meet specifications. However, in these cases,
the workability benefits of the plastomers may disappear, that is, for example, higher
temperatures may have to be used to process the asphalt and also to pave the roads.
This could lead to serious environmental pollution and could dramatically increase
energy costs.
[0007] The prior art includes
PCT publication WO2012103206, which relates generally to asphalt paving materials and methods for making asphalt
paving materials.
WO2012033490 discloses asphalt compositions and products comprising petroleum asphalt, polyolefin,
and a wax.
DE2033300 discloses moulding compositions of polypropylene and bitumen.
WO2014043021 discloses bitumen compositions and methods of making the same.
WO2011100033 discloses methods of preparing a cross-linked, polymer-modified asphalt.
EP0139883 discloses polyolefin and asphalt compositions; more particularly, sulfur stabilized
oxidized polyolefin and asphalt compositions containing oxidized polyethylene.
[0008] Accordingly, it is desirable to provide asphalt binders with plastomers such that
the asphalt binders meet MSCR criteria. In addition, it is desirable to provide asphalt
binders with plastomers that result in asphalt binders that meet MSCR criteria without
requiring elastomers. It is further desirable to provide asphalt paving material that
includes such asphalt binders and that are useful without substantially increasing
environmental pollution or energy costs. It also is desirable to provide methods for
fabricating such asphalt binders. Furthermore, other desirable features and characteristics
of the present invention will become apparent from the subsequent detailed description
of the invention and the appended claims, taken in conjunction with the accompanying
drawings and this background of the invention.
BRIEF SUMMARY
[0009] Plastomer-modified asphalt binders meeting MSCR specifications, asphalt paving materials
with such asphalt binders, and methods for fabricating such asphalt binders are provided.
In an exemplary embodiment, an asphalt binder contains a base asphalt and a plastomer
having a drop point of from about 152 °C to about 167 °C, and wherein the asphalt
binder is substantially free of elastomer. The asphalt binder may further comprise
sulfur; sulfur-containing compounds, such as hydrocarbyl polysulfides and thiuram
disulfides; phenolic resins; metal oxides; or a combination thereof.
[0010] In accordance with another exemplary embodiment, an asphalt paving material includes
an asphalt binder comprising a base asphalt and a plastomer having a drop point of
from about 152 °C to about 167 °C, wherein the asphalt binder is substantially free
of elastomer. The asphalt paving material may further comprise sulfur; sulfur-containing
compounds, such as hydrocarbyl polysulfides and thiuram disulfides; phenolic resins;
metal oxides; or a combination thereof. The asphalt paving material also comprises
an aggregate.
[0011] In accordance with a further exemplary embodiment, a method for fabricating an asphalt
binder includes heating a base asphalt to a sufficiently liquid state, and combining
the base asphalt and a plastomer having a drop point greater than 139°C, wherein the
asphalt binder is substantially free of elastomer. The base asphalt may be heated
to a temperature of about 75 to about 200 °C. The plastomer may be selected from:
(i) a maleated polypropylene with a drop point of about 152 °C and a saponification
number of from about 75 to about 95 mg KOH/gm; (ii) a maleated polypropylene with
a drop point of about 155 °C and a saponification number of about 14 to about 22 mg
KOH/gm; (iii) a polypropylene with a drop point of 167 °C and a saponification number
of about 0; or (iv) an oxidized high density polyethylene with has a drop point of
approximately 140 °C and an acid number of 7 mg KOH/gm. In some embodiments, (a) sulfur;
(b) sulfur-containing compounds, such as hydrocarbyl polysulfides and thiuram disulfides;
(c) phenolic resins; (d) metal oxides; or (e) a combination thereof may also be incorporated
into the base asphalt.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The various embodiments will hereinafter be described in conjunction with the following
drawing figures, wherein like numerals denote like elements, and wherein:
FIG. 1 is a table illustrating the results of MSCR tests of asphalt binders containing
plastomers exhibiting various drop points. The asphalt binders are formed from a PG
64-22 base asphalt from the mid-continent region of the United States. The tests are
conducted at the operational environmental temperature of 64°C; and
FIG. 2 is a graph illustrating the results of FIG. 1.
DETAILED DESCRIPTION
[0013] The following detailed description is merely exemplary in nature and is not intended
to limit the various embodiments or the application and uses thereof. Furthermore,
there is no intention to be bound by any theory presented in the preceding background
or the following detailed description.
[0014] The various embodiments contemplated herein relate to asphalt binders that include
a base asphalt and a plastomer. When the plastomer has a drop point of from about
152 °C to about 167 °C, the asphalt binder also may also contain (a) sulfur; (b) sulfur-containing
compounds, such as hydrocarbyl polysulfides and thiuram disulfides, particularly tetramethyl
thiuram disulfide (TMTD), tetraethyl thiuram disulfide (TETD) and tetrabutyl thiuram
disulfide (TBUT); (c) phenolic resins, particularly phenol-aldehyde resin; (d) metal
oxides, such as zinc oxides; or (e) a combination thereof. The asphalt binders contemplated
herein can meet both the MSCR non-recoverable creep compliance, J
nr specification and also the MSCR stress sensitivity J
nr,diff specification without the presence of elastomers. In this regard, they can be used
to fabricate asphalt paving materials at lower temperatures than if elastomers were
present and result in lower temperature road paving while also effectively facilitating
reduced road rutting.
[0015] Methods for measuring an asphalt binder's performance have changed over time, exposing
shortcomings of conventional asphalt binders. The Performance Graded (PG) System is
a method of measuring asphalt binder performance that was originally developed during
the Strategic Highway Research Project Program in the United States in the early 1990's.
The Superpave™ performance grading (PG) specification classifies asphalt binders into
performance grades that change at 6°C intervals according to service climate. For
example, a Superpave Performance Grade PG 64-22 meets high temperature physical properties
up to 64°C and low temperature physical properties down to -22°C. While this system
works well for conventional-speed, moderate-traffic volume pavements, research indicates
that it needs some refinement for pavements that have slow-speed loading and high
traffic volume. Rather than change criteria and/or test conditions to reflect a change
in loading time and traffic volume, in the PG System traffic speed and volume are
adjusted for by "grade-bumping" or testing at higher temperatures than indicated by
the climate. For example, for a standard traffic asphalt pavement, a PG 64-22 asphalt
binder might be used but a high-volume highway pavement might require a PG 76-22 asphalt
binder - even though the pavement temperature would likely never get above 64°C.
[0016] More recent research has resulted in the Multiple Stress Creep Recovery (MSCR) test,
with the methodology described in AASHTO T350-14 and the specification in AASHTO M332-14.
The MSCR test provides the user with a new high temperature binder specification that
is intended to more accurately indicate the rutting performance of the asphalt binder.
The MSCR test uses the well-established creep and recovery test concept to evaluate
the binder's potential for permanent deformation. Using the Dynamic Shear Rheometer
(DSR), the same piece of equipment used in the existing PG specification, a one-second
creep load is applied to the asphalt binder sample, which has been short-term aged
using the Rolling Thin Film Oven (RTFO). After the 1-second load is removed, the sample
is allowed to recover for 9 seconds. The test begins with the application of a low
stress (0.1 kPa) for 10 creep/recovery cycles, then the stress is increased to 3.2
kPa and repeated for an additional 10 cycles. The average of the non-recoverable strain
divided by the applied stress (for both 0.1 and 3.2 kPa) at ten loading cycles are
the non-recoverable creep compliance, J
nr.
[0017] A major difference between the MSCR specification and the PG System is how grade
bumping is done. With the MSCR specification, the binder testing is done at the high
environmental temperature that the pavement is expected to experience. If the climate
grade is a PG64 or PG58, all high temperature testing is conducted at 64°C or 58°C.
If heavy traffic is expected the specification requirement is changed, i.e., a lower
J
nr value is required to reflect the increased stress the pavement will actually experience,
but testing is still done at, for example, 64°C for a PG 64 climate. For example the
MSCR specification J
nr for standard fast moving traffic is a maximum of 4.5 kPa
-1 and for slow moving or higher traffic the required J
nr value would be a maximum of 2.0, 1.0 or 0.5 to require a more rut-resistant material
instead of testing at a higher temperature. High temperature testing for each S, H,
V or E grades (as explained below) would be done at the same pavement climate temperature
of, for example, 58°C or 64°C. This allows for accurate evaluation of the binder at
the expected operating temperature. A section of the AASHTO specification is shown
in Table 1 below, where grade bumping is done by changing the required specification
value of standard, heavy, very heavy, or extreme traffic, not by changing temperature.
Table 1: The MSCR gradings reflect the current grade bumping limits.
Standard S grade |
traffic < 3 million ESAL's |
Heavy H grade |
traffic > 3 million ESAL's |
Very Heavy V grade |
traffic > 10 million ESAL's |
Extreme E grade |
traffic > 30 million ESAL's |
where "ESAL's" is "equivalent single axle loads."
[0018] The stress sensitivity parameter J
nr,diff, is calculated using the equation J
nr.diff = (J
nr, 3.2kPa - J
nr,0.1kPa)/J
nr,0.1kPa. The J
nr, diff is required under the MSCR specification to be below 75% to ensure that the binder
will not be overly stress sensitive to unexpected heavy loads or unusually high temperatures.
[0019] As noted above, the asphalt binder as contemplated herein includes a base asphalt.
All types of asphalt, naturally occurring and synthetically manufactured, may be used
in accordance with the asphalt binders contemplated herein. For example, industrial
asphalts used for pavings, coatings, sealants, roofing materials, adhesives, and other
applications may be used. Asphalt is defined by the ASTM as a dark brown to black
cementitious material in which the predominant constituents are bitumens that occur
in nature or are obtained in petroleum processing. Asphalts characteristically contain
saturates, aromatics, resins and asphaltenes. Naturally occurring asphalt is inclusive
of native rock asphalt, lake asphalt, and the like. Synthetically manufactured asphalt
is often a byproduct of petroleum refining or post refining operations and includes
air-blown asphalt, blended asphalt, cracked or residual asphalt, petroleum asphalt,
propane asphalt, straight-run asphalt, thermal asphalt, and the like.
[0020] The asphalt binder also includes a plastomer. As used herein, the term "plastomer"
generally refers to polymers possessing moderate to high degrees of crystallinity
that enhance the stiffness of an asphalt binder but provides little, if any, elasticity.
In one exemplary embodiment, the plastomer contemplated herein has a drop point greater
than 139°C. The drop point is defined by ASTM D3954. The drop or dropping point is
a characteristic property of a material and is the temperature at which the first
drop of the material falls from a cup under defined test conditions. Examples of plastomers
suitable for use in the asphalt binders contemplated herein include maleated polypropylenes,
such as, for example, Honeywell Titan™ 7278, which has a drop point of about 152°C
and a saponification number of from about 75 to about 95 mg KOH/gm, Honeywell Titan™
7933, which has a drop point of about 155°C and a saponification number of about 14
to about 22 mg KOH/gm; oxidized high density polyethylenes (defined as polyethylenes
with a density of about 0.94 to about 1.0 gm/cm
3), such as, for example, Honeywell Titan™ 7817, which has a drop point of approximately
140°C and an acid number of 7 mg KOH/gm; and polypropylenes, such as, for example
Honeywell Titan™ 7457, which has a drop point of 167°C and an acid number or a saponification
number of about 0. All Honeywell Titan™ products are available from Honeywell International,
Inc. of Morristown, New Jersey. In an embodiment, the plastomer or a mixture of plastomers
is present in the asphalt binder in an amount no greater than 10 weight percent (wt.%)
based on the total weight of the asphalt binder. These values represent the concentration
for the final in-use asphalt binder. Higher concentrations can be used to make concentrates
that are subsequently "let down" to the final in-use concentration.
[0021] The asphalt binder is substantially free from elastomer. To the extent that the asphalt
binder contains elastomer, it contains an amount that does not modify or amend the
physical, mechanical or chemical properties of the asphalt binder. In one embodiment,
the asphalt binder contains no more than 1 wt.% elastomer based on the total weight
of the asphalt binder. As used herein, the term "elastomer" refers to a polymer that
can enhance the stiffness of an asphalt binder and also impart elasticity.
[0022] In another exemplary embodiment, the asphalt binder includes an additive chosen from
sulfur; sulfur-containing compounds, such as hydrocarbyl polysulfides and thiuram
disulfides, particularly tetramethyl thiuram disulfide (TMTD), tetraethyl thiuram
disulfide (TETD) and tetrabutyl thiuram disulfide (TBUT); phenolic resins, particularly
phenol-aldehyde resin; metal oxides, such as zinc oxides; or a combination thereof.
One or more of these additives can facilitate lowering of both non-recoverable creep
compliance, J
nr, and also the stress sensitivity parameter J
nr,diff, of the asphalt binder such that when used in combination with a plastomer, the plastomer
no longer needs a drop point greater than 139°C, although more plastomer may be required
to make the same MSCR grade. In one embodiment, the sulfur is added to the asphalt
binder as elemental sulfur. In an exemplary embodiment, the additive is present in
the asphalt binder in an amount greater than zero and no greater than about 1 wt.%
based on a total weight of the asphalt binder.
[0023] In one embodiment, an asphalt paving material contains the asphalt binder contemplated
herein. In addition to the asphalt binder described above, the asphalt paving material
includes an aggregate. "Aggregate" is a collective term for mineral materials, such
as, for example, sand, gravel, or crushed stone that are combined with the asphalt
binder to form the asphalt paving material. The aggregate may comprise natural aggregate,
manufactured aggregate, or a combination thereof. Natural aggregate is typically extracted
rock from an open excavation (e.g. a quarry) that is reduced to usable sizes by mechanical
crushing. Manufactured aggregate is typically a byproduct of other manufacturing processes
such as slag from metallurgical processing (e.g. steel, tin, and copper production).
Manufactured aggregate also includes specialty materials that are produced to have
a particular physical characteristic not found in natural rock, such as, for example,
low density. The gradation of the aggregates is carefully controlled in a hot mix
design to optimize its performance. Hot mix designs can be categorized in "dense graded,"
Stone Matrix Asphalt (SMA), Open Graded Friction Course (OGFC) and the like based
on the relative proportions of the aggregate sized. In an exemplary embodiment, about
3 to about 8 wt.% of the asphalt binder is mixed with about 92 to about 97 wt.% aggregate
to form an asphalt paving material. Other well-known additives also can be added to
the hot mix, including anti-stripping materials, warm mix additives, fibers and the
like.
[0024] In an exemplary embodiment, a method for preparing an asphalt binder as contemplated
herein is provided. The method includes heating the base asphalt to a sufficiently
liquid state such that the plastomer and any other modifier can be more easily incorporated.
In one embodiment, the base asphalt is heated to a temperature of about 75 to about
200°C. For faster incorporation, the temperature can be above the melting point of
the plastomer. The asphalt can be neat or can contain other additives at this point,
such as, for example, ground tire rubber (GTR), reclaimed asphalt pavement (RAP),
reclaimed asphalt shingle (RAS), phosphoric acid, polyphosphoric acid, ethylene/vinyl
acetate copolymer, and the like, or various combinations of these modifiers. The asphalt
and a plastomer as contemplated herein are combined using, for example, a low shear
mixer at a sufficient mixing speed to homogeneously incorporate the plastomer into
the asphalt within a reasonable time frame. In a lab, for example, the low shear mixer
can operate with a mixing speed of from about 5 to about 800 revolutions per minute
(RPM). If the asphalt does not yet contain sulfur; sulfur-containing compounds, such
as hydrocarbyl polysulfides and thiuram disulfides; phenolic resins; metal oxides;
or a combination thereof, one or more of these additives can be added to the asphalt
binder at this time. The mixing continues for a time sufficient to make a homogeneous
blend, such as about 30 minutes to about four hours.
[0025] Table 1 illustrates the results of tests of stress sensitivity J
nr,diff of asphalt binders containing plastomers exhibiting two different drop points. The
asphalt binders are formed from two different base asphalts, PG 64-22A and PG 64-22B,
both from the mid-continent region of the United States. The asphalt binders contained
97.55 wt.% base asphalt and 2.45 wt.% plastomer. The tests are conducted at the operational
environmental temperatures of 64°C and 76°C.
Table 1
polymer |
drop point (°C) |
Jnr-diff @ 64 ° C |
64-22A |
64-22B |
Honeywell Titan™ 7686 |
136 |
42.20% |
68.26% |
Honeywell Titan™ 7278 |
152 |
26.80% |
35.51% |
Polymer |
drop point (°C) |
Jnr-diff @ 76°C |
64-22A |
64-22B |
Honeywell Titan™ 7686 |
136 |
125.05% |
133.74% |
Honeywell Titan™ 7278 |
152 |
30.18% |
47.65% |
As Table 1 shows, the asphalt binders with a plastomer having a drop point below 139°C
(Comparative Example) had higher J
nr,diff values than the plastomer with the drop point above 139°C (Example) and failed the
MSCR specification at 76°C, that is, the J
nr,diff is above 75%, while the asphalt binders with a plastomer having a drop point above
139°C passed the MSCR specification, that is, the J
nr,diff is significantly below 75% at both testing temperatures.
[0026] FIG. 1 illustrates the results of tests of stress sensitivity J
nr,diff performed on asphalt binders containing seven different plastomers. Three of the
asphalt binders contained plastomers exhibiting different drop points below 139°C
(Comparative Examples), that is, 136°C, 126.5°C, and 126°C. As shown in FIG. 1, these
three different asphalt binders failed the MSCR specification with J
nr,diff above 75%. The asphalt binders with plastomers having drop points above 139°C (Examples)
all passed the MSCR specification. FIG. 2 is a graphic illustration of FIG. 1 with
the plastomer drop points on the x-axis 10 and J
nr,diff on the y-axis 20. From FIG. 2 it appears that as the drop point of the plastomer
added to the asphalt binder increased, J
nr,diff of the asphalt binder decreased.
[0027] Table 2 illustrates the effects of sulfur on asphalt binders contemplated herein.
Results of non-recoverable creep compliance, J
nr, and stress sensitivity J
nr,diff tests performed on a neat asphalt binder and the asphalt binder with plastomers having
two different drop points are shown. The asphalt binder 64-22 E was from the mid-continent
region of the United States. Honeywell Titan™ 7205 is a mid-density (a density of
about 0.925 to about 0.94 gm/cm
3) polyethylene homopolymer with a drop point of 115 °C and Honeywell Titan™ 7278 has
a drop point of 152°C.
TABLE 2
Composition |
|
|
|
|
|
|
|
PG 64-22 E |
100.00% |
99.90% |
97.00% |
96.9% |
97.3% |
97.5% |
97.4% |
Honeywell Titan™ 7205 |
|
|
3.0% |
3.0% |
2.5% |
|
|
Honeywell Titan™ 7278 |
|
|
|
|
|
2.5% |
2.5% |
Sulfur |
|
0.1% |
|
0.1% |
0.2% |
|
0.1% |
Total |
1.00 |
1.00 |
1.00 |
1.00 |
1.00 |
1.00 |
1.00 |
MSCR Specification |
Temp (°C) |
|
|
|
|
|
|
|
Jnr, 3.2kPa (kPa-1) |
64 |
2.570 |
2.120 |
1.047 |
0.865 |
0.975 |
1.170 |
0.873 |
Jnr diff <= 75% |
64 |
8.88% |
10.35% |
102.78% |
71.83% |
53.79% |
29.52% |
26.35% |
MSCR grade |
64S |
64S |
failed |
64V |
64V |
64H |
64V |
As shown in Table 2, for the neat asphalt binder, the addition of sulfur caused the
non-recoverable creep compliance, J
nr, to drop slightly, although the MSCR grade remained the same at "S." The asphalt
binder with the 3 wt.% plastomer having a drop point no greater than 139°C failed
the stress sensitivity parameter J
nr,diff specification. However, the addition of 0.1% sulfur caused the asphalt binder to
exhibit an "V" grade in addition to passing the stress sensitivity parameter J
nr,diff specification. The addition of 0.2% sulfur to the binder containing 2.5 wt.% plastomer
caused the asphalt binder to make a PG 64V grade and exhibit an even lower J
nr,diff value at 53.79%. Adding 2.5 wt.% plastomer with a drop point greater than 139°C (Honeywell
Titan™ 7278) to the neat asphalt binder dropped the J
nr value and raised the MSCR grade from an "S" to a "H." However, the addition of 0.1%
sulfur served to drop the J
nr value even further, raising the MSCR grade from an "H" to a "V" while also dropping
the J
nr,diff value. Thus, use of the plastomer with a drop point greater than 139°C enabled less
plastomer to meet the PG 64H-22 grade and less plastomer and less sulfur to meet the
PG 64V-22 grade.
1. An asphalt binder comprising:
a base asphalt; and
a plastomer having a drop point of from about 152 °C to about 167 °C; and
wherein the asphalt binder is substantially free of elastomer.
2. The asphalt binder of claim 1, wherein the plastomer comprises a maleated polypropylene
that has the drop point of about 152 °C and a saponification number of from about
75 to about 95 mg KOH/gm.
3. The asphalt binder of claim 1, wherein the asphalt binder further comprises sulfur,
sulfur-containing compounds, phenolic resins, hydrocarbyl polysulfides, metal oxides,
or a combination thereof.
4. The asphalt binder of claim 3, wherein the sulfur, sulfur-containing compounds, phenolic
resins, metal oxides, or a combination thereof is present in the asphalt binder in
an amount no greater than about 1 wt.% based on a total weight of the asphalt binder.
5. The asphalt binder of claim 1, wherein the plastomer is present in the asphalt binder
in an amount no greater than about 10 wt.% based on a total weight of the asphalt
binder.
6. The asphalt binder of claim 1, wherein the plastomer is selected from;
(i) a maleated polypropylene with a drop point of about 152 °C and a saponification
number of from about 75 to about 95 mg KOH/gm;
(ii) a maleated polypropylene with a drop point of about 155 °C and a saponification
number of about 14 to about 22 mg KOH/gm; or
(iii) a polypropylene with a drop point of 167 °C and a saponification number of about
0.
7. An asphalt paving material comprising:
an asphalt binder according to any one of claims 1 to 6; and
an aggregate.
8. A method for fabricating an asphalt binder, the method comprising the steps of:
heating a base asphalt to a sufficiently liquid state; and
combining the base asphalt and a plastomer having a drop point greater than 139 °C;
and
wherein the asphalt binder is substantially free of elastomer.
9. The method of claim 8, wherein the base asphalt is heated to a temperature of about
75 to about 200 °C.
10. The method of any of claims 8 or 9, wherein the plastomer is selected from;
(i) a maleated polypropylene with a drop point of about 152 °C and a saponification
number of from about 75 to about 95 mg KOH/gm;
(ii) a maleated polypropylene with a drop point of about 155 °C and a saponification
number of about 14 to about 22 mg KOH/gm;
(iii) a polypropylene with a drop point of 167 °C and a saponification number of about
0; or
(iv) an oxidized high density polyethylene with has a drop point of approximately
140 °C and an acid number of 7 mg KOH/gm.
1. Asphaltbinder, umfassend:
einen Basisasphalt; und
ein Plastomer mit einem Tropfpunkt von etwa 152 ºC bis etwa 167 ºC; und
wobei der Asphaltbinder im Wesentlichen frei von Elastomer ist.
2. Asphaltbinder nach Anspruch 1, wobei das Plastomer ein maleatiertes Polypropylen umfasst,
das einen Tropfpunkt von etwa 152 ºC und eine Verseifungszahl von etwa 75 bis etwa
95 mg KOH/g aufweist.
3. Asphaltbinder nach Anspruch 1, wobei der Asphaltbinder ferner Schwefel, schwefelhaltige
Verbindungen, Phenolharze, Hydrocarbylpolysulfide, Metalloxide oder eine Kombination
davon umfasst.
4. Asphaltbinder nach Anspruch 3, wobei der Schwefel, schwefelhaltige Verbindungen, Phenolharze,
Metalloxide oder eine Kombination davon in dem Asphaltbinder in einer Menge von nicht
mehr als etwa 1 Gew.-% vorhanden sind, basierend auf einem Gesamtgewicht des Asphaltbinders.
5. Asphaltbinder nach Anspruch 1, wobei das Plastomer in dem Asphaltbinder in einer Menge
von nicht mehr als etwa 10 Gew.-% vorhanden ist, basierend auf einem Gesamtgewicht
des Asphaltbinders.
6. Asphaltbinder nach Anspruch 1, wobei das Plastomer ausgewählt ist aus;
(i) einem maleatierten Polypropylen mit einem Tropfpunkt von ungefähr 152 °C und einer
Verseifungszahl von etwa 75 bis etwa 95 mg KOH/g;
(ii) einem maleatierten Polypropylen mit einem Tropfpunkt von etwa 155 °C und einer
Verseifungszahl von etwa 14 bis etwa 22 mg KOH/g; oder
(iii) einem Polypropylen mit einem Tropfpunkt von etwa 167 °C und einer Verseifungszahl
von etwa 0.
7. Asphaltierungsmaterial, umfassend:
einen Asphaltbinder nach einem der Ansprüche 1 bis 6; und
ein Aggregat.
8. Verfahren zum Herstellen eines Asphaltbinders, wobei das Verfahren die folgenden Schritte
umfasst:
Erhitzen eines Basisasphalts auf einen ausreichend flüssigen Zustand; und
Kombinieren des Basisasphalts und eines Plastomers mit einem Tropfpunkt von über 139
ºC; und
wobei der Asphaltbinder im Wesentlichen frei von Elastomer ist.
9. Verfahren nach Anspruch 8, wobei der Basisasphalt auf eine Temperatur von etwa 75
bis etwa 200 °C erhitzt wird.
10. Verfahren nach einem der Ansprüche 8 oder 9, wobei das Plastomer ausgewählt ist aus;
(i) einem maleatierten Polypropylen mit einem Tropfpunkt von ungefähr 152 °C und einer
Verseifungszahl von etwa 75 bis etwa 95 mg KOH/g;
(ii) einem maleatierten Polypropylen mit einem Tropfpunkt von etwa 155 °C und einer
Verseifungszahl von etwa 14 bis etwa 22 mg KOH/g;
(iii) einem Polypropylen mit einem Tropfpunkt von etwa 167 °C und einer Verseifungszahl
von etwa 0; oder
(iv) einem oxidiertem Polyethylen hoher Dichte mit einem Tropfpunkt von ungefähr 140
ºC und einer Säurezahl von 7 mg KOH/g.
1. Ciment asphaltique comprenant :
un asphalte de base ; et
un plastomère ayant un point de goutte d'environ 152 °C à environ 167 °C ; et
le ciment asphaltique étant sensiblement exempt d'élastomère.
2. Ciment asphaltique selon la revendication 1, dans lequel le plastomère comprend un
polypropylène traité au maléate qui a le point de goutte d'environ 152 °C et un indice
de saponification d'environ 75 à environ 95 mg KOH/g.
3. Ciment asphaltique selon la revendication 1, le ciment asphaltique comprenant en outre
du soufre, des composés contenant du soufre, des résines phénoliques, des polysulfures
d'hydrocarbyle, des oxydes métalliques ou une combinaison de ceux-ci.
4. Ciment asphaltique selon la revendication 3, dans lequel le soufre, les composés contenant
du soufre, les résines phénoliques, les oxydes métalliques ou une combinaison de ceux-ci
sont présents dans le ciment asphaltique en une proportion ne dépassant pas environ
1 % en masse par rapport à la masse totale du ciment asphaltique.
5. Ciment asphaltique selon la revendication 1, dans lequel le plastomère est présent
dans le ciment asphaltique en une proportion ne dépassant pas environ 10 % en masse
par rapport à la masse totale du ciment asphaltique.
6. Ciment asphaltique selon la revendication 1, dans lequel le plastomère est choisi
parmi :
(i) un polypropylène traité au maléate avec un point de goutte d'environ 152 °C et
un indice de saponification d'environ 75 à environ 95 mg KOH/g ;
(ii) un polypropylène traité au maléate avec un point de goutte d'environ 155 °C et
un indice de saponification d'environ 14 à environ 22 mg KOH/g ; ou
(iii) un polypropylène avec un point de goutte de 167 °C et un indice de saponification
d'environ 0.
7. Matériau asphaltique de pavage comprenant :
un ciment asphaltique selon l'une quelconque des revendications 1 à 6 ; et
un agrégat.
8. Procédé de fabrication d'un ciment asphaltique, le procédé comprenant les étapes consistant
à :
chauffer un asphalte de base à un état suffisamment liquide ; et
combiner l'asphalte de base et un plastomère ayant un point de goutte supérieur à
139 °C ; et
dans lequel le ciment asphaltique est sensiblement exempt d'élastomère.
9. Procédé selon la revendication 8, dans lequel l'asphalte de base est chauffé à une
température d'environ 75 à environ 200 °C.
10. Procédé selon l'une quelconque des revendications 8 et 9, dans lequel le plastomère
est choisi parmi :
(i) un polypropylène traité au maléate avec un point de goutte d'environ 152 °C et
un indice de saponification d'environ 75 à environ 95 mg KOH/g ;
(ii) un polypropylène traité au maléate avec un point de goutte d'environ 155 °C et
un indice de saponification d'environ 14 à environ 22 mg KOH/g ;
(iii) un polypropylène avec un point de goutte de 167 °C et un indice de saponification
d'environ 0 ; ou
(iv) un polyéthylène haute densité oxydé ayant un point de goutte d'environ 140 °C
et un indice d'acide de 7 mg KOH/g.